1. Field of the Invention
The invention relates to an image processing apparatus and an image processing method that are capable of expressing predetermined density information by printing a printing material on a printing medium.
2. Description of the Related Art
With professional use ink jet printing apparatuses the output of high grade images approaching that of photo quality is required, but it is not rare for there to be cases of outputting normal documents such as text or graphs. For such documents outputting at a high speed is more necessary rather than outputting at a high grade as silver halide photographs. Thus professional use ink jet printing apparatuses are endowed with multiple printing modes, and configured such that the user is capable of setting these modes according to the intended application. However, technical developments relating to image quality improvement can not always coexist with a printing mode that emphasizes less expensive or faster output. For example, in an ink jet printing apparatus configured such that the amount of ink ejected from the printing elements (referred to hereafter as ejection amount) can not be changed, in order to reduce graininess, all of the ink drops ejected from each of the printing elements aligned on the print head are small drops of a fixed amount. It is possible to obtain a desired density by aligning these dots, that are printed at a designated ejection amount, at a preferred density. As a result the printing resolution necessary for obtaining the desired density increases, and the necessary structural means and data processes become more complicated, as the ejection amount is made smaller in order to improve image quality. Accompanying this, also with respect to a mode that outputs at a higher speed, a state occurs wherein printing must depend on the above structural means and data processing method in order to obtain a desired density, and in which it is difficult to obtain a sufficient density at a satisfactory printing speed.
In order to resolve such issues, for example, Japanese Patent No. 4502362 discloses a printing configuration in which a high speed mode is provided that performs printing at a resolution lower than that of a high image quality mode, and wherein at the high speed mode, only with respect to pixels having a high density level, multiple overlapping dots are printed at 1 print pixel. With such a high speed mode even though printing is performed at a resolution lower than that of the high image quality mode, because it is possible to print inside a pixel the number of dots necessary for the desired density, suitable gradation characteristics can be obtained and a density insufficiency is not invited.
With respect to Japanese Patent No. 4502362, however, because the image processing of the high speed mode is carried out at a resolution lower than that of the image processing of the high image quality mode, tables for image processing (such as a color profile, for example) and programs for quantization must be independently provided for each of these 2 printing modes. In such case the memory necessary for image processing is enlarged. As well, a user that originally creates a color profile for image processing must create separate color profiles for the high speed mode and the high image quality mode, regardless of whether the printing mode is directed towards the same printing medium.